| Chronos Properties Ltd | Real estate | 2022 |
| Chuckle-Giggles Ltd | Professional & scientific | 2006 |
| Churchill Heating Ltd | Construction | 2017 |
| CHY Investment Limited | Real estate | 2018 |
| CIA Electrical & Security Services Ltd | Construction | 2024 |
| Cibikli Ltd | Hospitality | 2024 |
| Circuit Protection 24 Ltd | Wholesale & retail | 2022 |
| CIS Media Limited | Administrative & support | 2016 |
| Citadale Property Zone Ltd | Wholesale & retail | 2016 |
| Citihaulage Ltd | Extraterritorial | 2015 |
| City Line Electrics Ltd | Construction | 2026 |
| City Metalworks Ltd | Construction | 2019 |
| City Motors INT Ltd | Wholesale & retail | 2023 |
| City Premier Limited | Financial services | 2016 |
| City Tourism & Services Ltd | Financial services | 2019 |
| Ciubo Ltd | Transport & logistics | 2025 |
| CK Property Investors Ltd | Real estate | 2021 |
| Clark Facade Limited | Administrative & support | 2011 |
| Clark Fixing (1995) Limited | Construction | 1995 |
| Clarkes Terra Clean Services Ltd | Administrative & support | 2019 |
| Clean Point Services Ltd | Administrative & support | 2021 |
| Cleanmat Solutions Limited | Administrative & support | 2026 |
| Cleanovax Cleaning Services Ltd | Administrative & support | 2026 |
| Clear Scalps Ltd | Other services | 2025 |
| Clear Vision Solutions Ltd | Administrative & support | 2025 |
| Clinical PAD Limited | Information & communication | 2023 |
| Cloud Consultants Limited | Professional & scientific | 2025 |
| Cloud Shipping Services Ltd | Other services | 2017 |
| Clutty Cleaners Ltd | Administrative & support | 2018 |
| CM Mechanics Limited | Wholesale & retail | 2025 |
| CMC Scaffold and Cradle Limited | Construction | 2004 |
| CMI Progress Ltd | Construction | 2026 |
| CMS Properties UK Services Ltd | Real estate | 2021 |
| CNC Taxis Ltd | Transport & logistics | 2008 |
| Cobblehill Limited | Real estate | 2023 |
| Cobbler ELF Ltd | Other services | 2017 |
| Coco Emporium Ltd | Wholesale & retail | 2020 |
| Codruta Consulting Ltd | Administrative & support | 2025 |
| Coelco Trading Limited | Administrative & support | 1996 |
| Cognitive Solutions Intl Limited | Wholesale & retail | 2022 |
| Colestone Developments Ltd | Construction | 2026 |
| Collecthub Limited | Information & communication | 2023 |
| Combine HQ Ltd | Information & communication | 2023 |
| Combined Real Estates Ltd | Real estate | 2020 |
| Comcrafts Ltd | Wholesale & retail | 2020 |
| Comfort Zone Technology Limited | Administrative & support | 2012 |
| Commodum Handel Limited | Wholesale & retail | 2022 |
| Community Pharmacy Supplies Limited | Health & social care | 2005 |
| Compound Projects Ltd | Construction | 2024 |
| Comprie Estates Ltd | Real estate | 2023 |
| Comprie Ltd | Other services | 2012 |
| Computer Master Ltd | Wholesale & retail | 2020 |
| Conation Project Management Ltd | Professional & scientific | 2019 |
| Concept Finance Ltd | Wholesale & retail | 2007 |
| Concord Security Ltd | Administrative & support | 2019 |
| Concrete Supply Services Limited | Other services | 2022 |
| Confix Ltd | Construction | 2023 |
| Congolese Diaspora Network CIC | Financial services | 2026 |
| Consolidated Projects Ltd | Administrative & support | 2024 |
| Consulaw Technologies Ltd | Information & communication | 2026 |
| Consult Base Global Ltd | Professional & scientific | 2020 |
| Consultivo Projects Ltd | Administrative & support | 2021 |
| Contract Rail Limited | Manufacturing | 2018 |
| Cooltech Packaging Ltd | Administrative & support | 2023 |
| Cooper RUM Ltd | Manufacturing | 2024 |
| Copia Softech Limited | Other services | 2025 |
| Coralbank Solutions Limited | Construction | 2008 |
| Cordybiotech Ltd | Wholesale & retail | 2021 |
| Core Facilities Solutions Limited | Wholesale & retail | 2024 |
| Core Security Systems Ltd | Administrative & support | 2008 |
| Cornerstone ASC Ltd | Education | 2016 |
| Corporate Creations London Limited | Information & communication | 2025 |
| Cosek Education Ltd. | Education | 2008 |
| Cost and Planning Services UK Ltd | Real estate | 2012 |
| Costless Xpress Ltd | Wholesale & retail | 2026 |
| Count Your Blessings [CYB] Ltd | Health & social care | 2022 |
| County Construction Service Limited | Construction | 2010 |
| County Line Recovery's Ltd | Transport & logistics | 2025 |
| County Maintenance Ltd | Construction | 2026 |
| Cozaru Ltd | Construction | 2026 |
| Cozzy Solutions Ltd | Construction | 2025 |
| CPS Fitness Ltd | Arts & recreation | 2026 |
| Craft & Core NN Ltd | Construction | 2026 |
| Crainic's Handy Services Ltd | Construction | 2018 |
| Crawford Glass of London Limited | Construction | 2004 |
| Creadoh Properties Ltd | Real estate | 2025 |
| Cream & Crumble Ltd | Hospitality | 2024 |
| Creativa Digital Limited | Other services | 2024 |
| Crestpoint Limited | Wholesale & retail | 2019 |
| Cris Hairdressing Ltd | Other services | 2025 |
| Cristan Ltd | Transport & logistics | 2016 |
| Crossbridge Partners Limited | Professional & scientific | 2024 |
| Crowdcue Limited | Hospitality | 2024 |
| Crownlink Associates Limited | Wholesale & retail | 1999 |
| Crownz & Co Strategies Limited | Information & communication | 2025 |
| Crystal Diamonds Cleaning Ltd | Administrative & support | 2024 |
| Crystalize Care Services Ltd | Health & social care | 2017 |
| CS - Draft Limited | Professional & scientific | 2019 |
| CT Drywall Ltd | Construction | 2024 |
| CT Trans Ltd | Transport & logistics | 2020 |